Hot applied plastisol compositions

ABSTRACT

Thermally stable hot applied plastisol compositions are especially useful in the assembly of metal parts. The compositions have adhesive and sealant qualities which allow them to be used in automotive assembly plants. Compositions of the invention comprise as major ingredients finely divided polyvinyl chloride resin, plasticizer, thermoplastic polymeric resin which is solid at room temperature but softens to a flowable state at application temperature, and an adhesion promotion system. Optionally a filler, wax, heat stabilizer, pigment, wetting agent, or mixtures thereof may be added. The individual components work synergistically to get good application properties, metal adhesion, wash-out resistance, and paintability.

This is a continuation of application Ser. No. 301,702, filed Jan. 26,1989 now U.S. Pat. No. 4,900,771.

This invention relates to plastisol compositions. More particularly theinvention relates to thermally stable plastisol compositions which arecapable of being hot applied to metal surfaces for adhesive and sealantpurposes.

Adhesive and sealant compositions are widely used in many commercial andindustrial production processes. A multitude of such compositions havebeen developed over the years, many of which were designed for a specialuse. Adhesive compositions generally are used to bind two substratestogether. Sealant compositions generally are used to form a load-bearingelastic joint between two substrates. The sealants also exclude dirt,moisture and other materials from the joint and form a smooth junctureat the joint. Necessarily, there is some overlap in the functions of theadhesive and sealant compositions.

The automotive industry is a major user of both adhesive and sealantcompositions. Automobiles are assembled from several structuralcomponents. The components are joined together in various fashionsdepending on the particular components and the degree of stress thatwill have to be endured. For certain assembly steps an adhesivecomposition applied as a liquid and subsequently hardened providessufficient bonding strength. For example, metal assemblies of doorpanels, quarter panels, tailgates, and roofs use adhesive compositions.These same assemblies also use sealant compositions at a later stage inthe assembly line. Still other automobile assemblies which are welded orbolted together use sealant compositions in their seams. The wheelhouse, shock tower, rocker panel, firewall, floor hem flange, floorpan,and trunk are a few examples of where sealants, but not adhesives, areused.

Typical automobile body assembly lines contain a separate body shop andpaint shop areas where adhesives and sealants are individually used ineach area respectively. Adhesive compositions applied in the body shoparea are normally high strength epoxy or modified-epoxy adhesives whichare capable of bonding to oily galvanized steel. In some cases vinylplastisols are employed, however, these applications are normallylimited to situations that do not require high bonding performance. Inany case, these materials are applied at room temperature and latercured through exposure to heat. A current weakness of these materials isthat in order to apply them, they must be of low enough viscosity to bemechanically pumped with adequate flow rates. Normally, because of theirlow viscosity these materials are easily displaced when exposed toliquid impingement by various cleaning solutions (washes) to which theassembly body parts are exposed.

Recently a new class of materials referred to as curing hot appliedadhesives have been introduced in the automotive body shop. These areurethane or epoxy-modified urethanes and are solid or semi-solid at roomtemperature. These adhesives function by changing from a flowable fluidat an elevated application temperature to a bonding solid at usetemperature. The hot applied adhesives have a number of characteristicswhich make them attractive for use in the body shop area. They areusually solvent free and thus no special fume collection hoods areneeded. They have low viscosities when made fluid and thus flow readilyto fill gaps and wet the substrates to be bonded. Most importantly theresins after application provide a high strength bond and cure to aneven higher strength after passage through drying ovens at a later stageon the line. Additionally, the applied adhesive compositions have arapid set time. They will not be displaced when exposed to liquidimpingement by various washes and electrophoretic priming fluids towhich the assembled body parts are subjected.

The assemblied parts as they move from the body shop area are subjectedto sealing, painting, and final oven curing in the paint shop area.Sealant compositions used in this area must also have a certain set ofcharacteristics to be acceptable. Vinyl plastisol compositions have beenfound to have those needed characteristics. Basically, a vinyl plastisolis a finely divided polyvinyl chloride resin suspended in a plasticizer.The plastisols are liquids which are applied at room temperature to thesubstrate. The liquid is converted to a solid through exposure to heat.In effect, the heat causes the suspended resin particles to be fused ordissolved in the plasticizer. A solid product results upon subsequentcooling.

Vinyl plastisols are excellent as sealants in the paint shop area of thebody assembly line. They flow readily at room temperature to fill seamsand body joints which need to be sealed. They adhere well to primedmetal surfaces. They can be painted over without leaching or causingother cosmetic problems. Finally, they are durable enough to withstandnormal weather and user exposure. Another important quality of the vinylplastisols is that they are not expensive. The plastisols would ideallybe used in all adhesive and sealing phases of the automotive assemblyprocess if they had better metal bonding properties and could withstandthe washes and primer applications experienced in the body shop area ofthe process.

Accordingly, a need exists for a product with both strong adhesive andexcellent sealant properties and for compositions which combine thecharacteristics of both the curing hot applied adhesives and the vinylplastisols.

SUMMARY OF THE INVENTION

That need is met by the present invention which provides a thermallystable hot applied plastisol composition. That composition has a host ofqualities which makes it attractive for bonding and/or sealing jointsareas in metal assemblies such as automobile bodies and parts thereof.

The hot applied thermally stable plastisol composition of the presentinvention comprises as a principal component thereof from about 20% toabout 35% of a finely divided polyvinyl chloride resin. The compositionpreferably contains a mixture of two polyvinyl chloride resins whichcomprise about 23-32% and most preferably about 25-30% of thecomposition. The first resin may be a homopolymer dispersion resin withinherent viscosity of about 1.00 ml/g and is preferably between 50 and100% and most preferably between 50% and 75% of the resin system. Thesecond resin is a blending resin that may be a copolymer of vinylchloride and maleic ester with inherent viscosity of about 0.97 ml/g andis preferably between 0 and 50% and most preferably between 25% and 50%of the resin system. PG,6

A second major component of the present composition is from about 15% toabout 35% of a plasticizer. The plasticizer is preferably diisodecylphthalate and preferably is about 19-30% and most preferably about22-30% of the composition.

Also included is about 2-25% of a thermoplastic polymeric resin,preferably about 5-20% and most preferably about 10-15% of a vinylacetate/ethylene copolymer having a vinyl acetate content preferably ofabout 50-70% and most preferably about 60-65%.

Finally there is present about 3-15% of an adhesion promotion system.The adhesion promotion system preferably comprises about 5-13% and mostpreferably about 5-11% of the total composition. The adhesion promotionsystem preferably contains an unsaturated organosilane (between about0.1 and 1% of the total composition and 2.7-5.0% of the adhesionpromotion system), an acrylic monomer (between 2 and 8% of the totalcomposition and 54.0-40.0% of the adhesion promotion system), anunsaturated acid or anhydride monomer (between 0.1 and 2% of the totalcomposition and 2.7-10.0% of the adhesion promotion system) an epoxy ormodified epoxy resin (between 0.5 and 4% of the total composition and13.5-20.0% of the adhesion promotion system) and a hardening agent forthe epoxy resin, such as a polyamide (between 1 and 5% of the totalcomposition and 27.0-25.0 of the adhesion promotion system).

Optionally the composition also contains filler. waxes, heatstabilizers, pigment, wetting agents and various combinations andmixtures thereof.

the composition of the present invention has both adhesive and sealantcharacteristics which make it especially useful in the assembly of metalautomotive parts. The plastisol composition of the present invention isthermally stable, can be hot applied to automotive parts for adhesiveand sealant purposes, and can subsequently withstand the successivesteps of a primer application, primer wash-off, top coat paintapplication and oven bake.

The preferred method of bonding and/or sealing using the presentcomposition involves hot applying the plastisol composition to jointareas of a metal assembly, followed by cooling the compositionsufficiently to achieve sufficient bonding. If an automobile body or apart thereof is being sealed in this manner, the method may in someinstances further involve applying a primer composition to the metalassembly, heating the metal assembly to cure the primer, and applyingadditional plastisol composition to joint areas to form a sealed smoothsurface. In any event, it will usually involve applying a paintcomposition to the metal assembly, and baking the metal assembly to curethe plastisol composition and the paint composition.

Accordingly, it is an object of the present invention to provide a hotapplied thermally stable plastisol composition having adhesive andsealant qualities useful in the assembly of automobile bodies, and to amethod of bonding and/or sealing joint areas in metal assemblies usingsuch a composition. Other objects and advantages of the invention willbecome apparent from the following detailed description and the appendedclaims.

DETAILED DESCRIPTION OF THE INVENTION

As mentioned the composition of the present invention comprises as majoringredients finely divided polyvinyl chloride resin, plasticizer,thermoplastic polymeric resin and an adhesion promotion system. Each ofthe individual components of the composition will be discussed in detailas well as the composition's mode of use. All percentages and ratios areby weight unless otherwise stated.

Polyvinyl chloride resins used in the compositions of this invention arefinely divided resin particles which are capable of being dispersed in aplasticizer. The resins are well known and have been widely used inplastisol compositions. The polyvinyl chloride resins include polymersof vinyl chloride as well as copolymers of vinyl chloride withcopolymerizable vinyl addition monomers. Examples of such vinyl additionmonomers include vinyl acetate, the vinyl acetals, maleic esters,styrene, vinylidene chloride and acrylonitrile. The particularlypreferred polyvinyl chloride resins are the fine particle dispersiontype homopolymer resins and vinyl chloride/maleic ester copolymers in amonomer weight ratio of vinyl chloride to maleic ester of from about99:1 to about 90:10. Blends of several different polyvinyl chlorideresins may also be used and will also be referred to as the polyvinylchloride resin, even though more than one resin may actually be present.Actually, as mentioned, a blend of 50-100% and most preferably 50-75% ofa homopolymer dispersion resin and 0-50% and most preferably 25-50% of avinyl chloride/maleic ester copolymer blending resin is preferred.

Plasticizers useful in the present invention include monomeric typesselected to achieve desired characteristics such as proper gelation,fusion, and flow properties. Examples of such monomeric plasticizersinclude monomeric esters of phthalic, benzoic, succinic, adipic,sebacic, talic, lauric, azelaic, caprylic, hexanoic, phosphoric, oleic,glutaric, trimellitic and stearic acids. Specific plasticizers includedioctyl phthalate, ethylene glycol dibenzoate, dioctyl succinate,dibutyl sebacate; dibenzyl azelate; didecyl glutarate and similarcompounds. Other monomeric plasticizers include esters of 2, 2,4-trimethyl-1,3-pentanediol, citric acid esters and n-ethyltoluenesulfonamide. Preferred is diisodecyl phthalate.

Polymeric plasticizing agents can be used in conjunction with themonomeric plasticizers in order to achieve special characteristics suchas permanence, weathering resistance, and especially paintability.Polymer plasticizers useful in the present invention include the highermolecular weight polymeric acid esters (molecular weights greater than1000). Examples of these polymeric plasticizers include esters ofsuccinic, adipic, sebacic, talic, lauric, azelaic, caprylic, hexanoic,benzoic, phthalic, phosphoric, oleic, glutaric, trimellitic, and stearicacids, including mixtures or blends of these compounds. The polymericplasticizers have low diffusion rates because of their higher molecularweights and also act to retard the migration of other components fromthe applied compositions. Additionally, low molecular weight chlorinatedparaffinic oils and epoxidized soybean oil can be used as aco-plasticizers. Again, blends of several different plasticizers may beused, but will be referred to simply as the plasticizer.

A third essential component of the compositions is a thermoplasticpolymeric resin which is capable of softening at applicationtemperatures sufficiently to be flowable. Resins of this nature arecommonly referred to as hot applied resins. The resins are characterizedby their ability to set to a solid material by cooling rather than bysolvent evaporation or chemical reaction. Thus, the resins are reducedto a soft or molten state by increasing temeprature. Most of theseresins progressively soften over a wide temperature range, though somemay actually have very narrow melting ranges and becomes a true liquid.Each type of resin is useful herein and is referred to as a hot appliedresin. Typical resins are solid or semi-solid pastes at room temperaturewith softening temperatures of about 200° F. to about 375° F. Examplesof thermoplastic polymeric resins include the polyethylenes, polyamides,polyvinyl butyrals, polyvinyl acetates, cellulose derivatives,polyesters, polymethyl methacrylates and ethacrylates, polyvinyl ethersand polyurethanes. Specific examples of such thermoplastic resinsinclude ethylene ethyl acrylate copolymers, vinyl acetate styrenebutadiene block copolymers and butyl rubber.

Preferred thermoplastic resins are those polymers that show solubilityand compatibility with polyvinyl chloride polymers such as ethylenevinyl acetate, vinyl acetate ethylene, vinyl acetate, acrylonitrile,acrylonitrile butadiene copolymer, chlorinated ethylene vinyl acetate,polyepsilon caprolactone, methyl metacrylate and polybutyleneterephthalate. An ethylene vinyl acetate having a 20-80% vinyl acetatecontent is preferred. Vinyl acetate ethylene copolymers having a vinylacetate content of preferably 50-70% and most preferably 60-65% arehighly preferred because of their balance of compatibility, flow,adhesion and flexibility.

The adhesion promotion system found in the current compositionspreferably contains an unsaturated organosilane; an acrylic monomer; andan unsaturated acid or anhydride monomer. Most preferably it alsocontains an epoxy resin or modified epoxy resin and a hardening agentfor the epoxy resin, such as a polyamide or modified polyamide. All ofthe unsaturated materials are capable of polymerization with peroxideinitiation and heat. The formation of a highly functionalized oligomericor polymeric modified acrylic species in situ (after heating) in concertwith the reacted epoxy resin presumably is what is responsible for thetenacious bonding of the current adhesive to oily metals.

Examples of unsaturated organosilanes are the vinyl, acrylic andmethacrylic types such as vinyl trichlorosilane, vinyl triethoxy silane,vinyl trimethoxy silane, vinyl-tris β-methoxy-ethoxy silane,3-methacryloxypropyl trimethoxy silane, 3-methacryloxy propyl-tris-2(methoxy-ethoxy) silane and vinyl triacetoxy silane. Examples of acrylicmonomers are any of the free radical induced polymerizable mono ormultifunctional acrylic or methacrylic monomers such astrimethylopropane trimethacrylate, hexane diol diacrylate, and butylmethacrylate. Examples of unsaturated acid or anhydride monomers are thevinyl, acrylic, and methacrylic mono or poly functional acid oranhydride materials such as maleic, acrylic, crotonic, methacrylic,oleic, linoleic, and tetrahydrophthalic acid or anhydride.

Examples of unmodified epoxy resins are those based on bisphenol-A andepichlorohydrin with typical properties that includes an epoxy value of152-155 equiv./100 g and a weight per epoxide of 182-192. Other typicalepoxy resins are phenol novolac, triphenylolmethane, and tetrabromobis-A. An example of a modified epoxy resin includes the preferredelastomeric modified liquid epoxy resin which is a 40% adduct ofcarboxylated acrylonitrile butadiene elastomer and a liquid bisphenol-Aand epichlorohydrin type epoxy. That adduct has a weight per epoxide of325-375. Curing for the epoxy or modified epoxy resin is accomplished byreacting the resin with an appropriate curing or hardening agent.Typical hardening agents a polyamides, diethylenetriamine, methanediamine, m-phenylene diamine, diaminodiphenyl sulfone, tris (dimethylamino methyl) phenol, dicyandiamide, BF3-monoethyl amine and nadicmethylanhydride. Preferred is a modified polyamide hardening agent such as alatent polyamide dispersion which is an adduct of phthalic anhydride anddiethylenetriamine in an unmodified liquid epoxy resin. The epoxy ormodified epoxy resin/hardening agent system apparently modifies thegalvanized surface by reacting with and/or to the adhesion promotionsystem in the preferred embodiment.

It has been found that inclusion of the adhesion promotion system in thecompositions at the stated level significantly increases the adhesion ofthe composition to a metal surface without adversely affecting thequalities of the applied composition. That is, the composition'sresistance to primer wash, paintability, viscosity stability etc. arenot adversely affected by the adhesion promoter. Other adhesionpromoters are also preferably used with the current materials and,again, reference to the adhesion promoter is reference to the adhesionpromoter system unless otherwise indicated.

The compositions of the invention are fomulated with the above essentialcomponents to achieve a product having the desired set ofcharacteristics considering their intended use. The composition isintended as an adhesive and sealant for use in the assembly of metalautomotive parts. As such the compositions are able to flow atapplication temperature with the proper wet-out onto a surface, i.e.,they are "pumpable". Upon cooling an initial degree of adhesion isattained as discussed below. Additionally, because of the intended use,the set composition is capable of receiving a primer wash withoutexperiencing wash-out. Finally, the composition is able to accept aprimer and top coat paint and also to withstand multiple oven bakes. Thecomposition also has a final degree of adhesion which is very durable.

Optional components of the composition of the invention comprise waxes,heat stabilizers, fillers, pigments, and wetting agents. Such componentsare readily available. Amorphous waxes, carnauba wax, castor oil wax andvarious synthetic waxes was useful. Examples of heat stabilizers includelead and barium-cadmium-zinc systems. Fillers include ground andprecipitated calcium carbonate, ground silica, clays and talcs. Examplesof wetting agents are polyethylene glycol derivatives.

Compositions of the invention with the immediately aforedescribedqualities comprise (a) from about 20% to about 35% of the finely dividedpolyvinyl chloride resin, (b) from about 15% to about 35% of theplasticizer, (c) from about 2% to about 25% of the thermoplasticpolymeric resin, and (d) from about 3% to about 15% of the adhesionpromotion system. A preferred composition consists essentially (a) fromabout 23% to about 32% of the polyvinyl chloride resin, (b) from about19% to about 30% of the plasticizer, (c) from about 5% to about 20% ofthe thermoplastic polymeric resin, (d) from about 5% to about 13% ofadhesion promoter, and (e) the balance selected from the groupconsisting of a wax, heat stabilizer, filler, pigment, wetting agent,and mixtures thereof.

A particularly preferred composition in terms of performance and costconsiderations consists essentially of (a) from about 25% to about 30%of the polyvinyl chloride resin, (b) from about 22% to about 30% of aplasticizer, (c) from about 10% to about 15% of the thermoplasticpolymeric resin, (d) from about 5% to about 11% of adhesion promoter,(e) from about 15% to about 20% of a filler, (f) from about 0% to about8% wax, and (g) from about 1% to about 4% of a heat stabilizer

The aforedescribed compositions of the invention are unique in theirability to act as a structural adhesive and a sealant in the assembly ofautomotive bodies. Thus, the compositions are used in the body area ofthe assembly to bond various steel components such as hoods and roofpanels. Additionally, the compositions are used in the body shop areawhere certain components which demand greater structural bonds asobtained by welding require a sealant to smooth over the weld. Thecompositions are heated from about 90° F. to about 160° F. and appliedin any convenient manner, such as pumping, troweling, flowing, brushingor spraying. The compositions are thermally stable so that they can beheated and drawn from by a pumping operation for prolonged periods. Uponcooling the compositions harden to a state with an initial degree ofadhesion which is adequate for the intended purpose. This solidificationoccurs depite the plastisol nature of the compositions.

The assembled automotive body components or body shell is next preparedfor painting. Typically this involves phosphate cleaning, washing,immersing the body shell in a primer bath, applying an electric chargeto effect electrodeposition of the primer to the body shell, andremoving the primed body shell from the bath. The compositionsoriginally applied as adhesives and sealants remain in tack. That is,they are not washed out onto adjoining surface areas of the body shell.

Subsequent to the priming step, if one is used, and prior to an ovenbake, the body shell is top coated with a paint and oven baked to atotally cured state by plastisol fusion of the sealer and also the topcoat paint. The fusion temperature is well above the aforementionedapplication temperature. The applied compositions of the invention arealso able to withstand these operations without causing cosmetic-typeproblems such as discoloration, tackiness, cracking, etc.

It should be apparent the compositions of the invention enjoy all thequalities of previously used hot applied adhesive compositions and vinylplastisol compositions, collectively. The synergistic nature of thecomposition components without adverse properties is very unexpected. Anadded benefit flowing from one composition having such qualities isreduced inventory in not having to stock two separate products as wellas a consequent reduced administrative burden.

The following examples illustrate the invention.

EXAMPLE I

A preferred thermally stable hot applied plastisol composition has thefollowing formulation:

    ______________________________________                                                                  %                                                   ______________________________________                                        Polyvinyl chloride dispersion resin (1)                                                                   19.00                                             Polyvinyl chloride blending resin (2)                                                                     8.00                                              Diisodecyl phthalate plasticizer                                                                          28.00                                             Epoxidized soybean oil plasticizer (3)                                                                    2.00                                              Vinyl acetate ethylene copolymer thermoplastic resin                                                      13.00                                             (4)                                                                           3-methacryloxypropyl trimethoxy silane adhesion                                                           0.30                                              promoter (5)                                                                  Elastomeric modified liquid epoxy resin (6)                                                               2.00                                              Calcium organic thixotropic agent (7)                                                                     0.50                                              Methacrylate ester adhesion promoter (8)                                                                  4.50                                              Calcium carbonate filler (9)                                                                              8.04                                              Hydrophobic fumed silica filler (10)                                                                      8.00                                              Calcium oxide filler        2.00                                              Anionic surfactant wetting agent (11)                                                                     0.16                                              Modified polyamide hardening agent (12)                                                                   3.0                                               Cumene hydroperoxide        0.08                                              Tri-basic lead sulfate heat stabilizer (13)                                                               1.00                                              Hydroquinone monomethyl ether                                                                             0.02                                              Tetrahydrophthalic anhydride adhesion promoter                                                            0.30                                              Carbon black pigment        0.05                                              Titanium dioxide pigment    0.05                                                                          100.00%                                           ______________________________________                                         (1) A homopolymer available from Huls Corp. as Vestolit E 7031                (2) A copolymer of vinyl chloride and dibutyl maleate available from The      Goodyear Tire and Rubber Co. as Pliovic MC85                                  (3) Available from the C. P. Hall Co. as PlastHall ESO                        (4) A hot applied resin available from USI Chemicals Co. as Vynathene         EY80031                                                                       (5) Available from Dow Corning as Z6030 Silane                                (6) Available from Wilmington Chemical Corp. as Heloxy 8005.                   (7) Available from Ashland Chemical Co. as Ircogel 903                       (8) Available from Sartomer Co. as Chemlink 9010                              (9) Available from H. M. Royal Inc. as Roy Cal L                              (10) Available from Cabot Corp. as CabO-Sil TS720                             (11) Available from BYK Chemie USA as BykW 960                                (12) Available from CibaGeigy Corp. as Hardener HY 940                        (13) Available from Eagle Picher Co. as EPIstatic                        

The above composition was subjected to various tests to demonstrate itssuitability for the intended use. Initially the thermal stability of thecomposition at application temperature is determined. Samples of thecurrent composition were held in an oven at 120° F. and 140° F.respectively and the viscosity of each tested over a period of time.Viscosities of the samples, as expressed in centipoises adjusted to81.5° F. was as follows:

    ______________________________________                                        Hrs            120° F.                                                                         140° F.                                        ______________________________________                                        Initial        2,963,800                                                                              2,963,800                                             1              2,740,500                                                                              6,252,400                                             7              2,801,400                                                                              --                                                    ______________________________________                                    

The above results show that the composition's viscosity remainssubstantially constant at 120° F. for at least seven hours. At 140° F.,however, the viscosity of the composition increases significantly overtime. Thus, the composition is viscosity stable up to at least 120° F.

Another set of tests was used to show that the composition of thisexample has a sufficiently low viscosity at a pre-gel temperature to bepumpable. The viscosities of a sample of the composition is measured atvarious temperatures and plotted. Readings from the plot are as setforth below:

    ______________________________________                                        Temperature (°F.)                                                                     Viscosity (centipoises)                                        ______________________________________                                        75             1,640,240                                                      80             1,250,480                                                      85             990,640                                                        90             787,640                                                        100            519,680                                                        110            373,520                                                        120            292,320                                                        ______________________________________                                    

The above results show the viscosity of the composition decreases withtemperature and is low enough to be readily pumped at an applicationtemperature of about 120° F. The application temperature is lower thanthe temperature at which gelation begins.

EXAMPLE II

The formulation disclosed in Example I was tested for adhesive strengthon three galvanized steel substrates under various exposure conditions.The numbers reported are the force to detach 1"×4" metal coupons with a1 in.² bonded area pulled at 2"/minute. The specimens were heat curedfor 20 minutes at 325° F. and had a bond thickness of 0.030". An averagefailing force from three replicates is reported. % CF refers to the % ofcohesive failure for a given condition.

    __________________________________________________________________________    Adhesive Testing Results                                                      Shear Overlaps                                                                         HOT DIP                                                                              GALVANEAL                                                                             ELECTRO GALVANEAL                                     __________________________________________________________________________    Initial  389 100% CF                                                                          448 100% CF                                                                           463 100% CF                                           3 wks humidity                                                                         451  80% CF                                                                          477  67% CF                                                                           412  72% CF                                           3 wks 158° F.                                                                   654 100% CF                                                                          756 100% CF                                                                           659  93% CF                                           250 hrs. salt spray                                                                    441  53% CF                                                                          550  57% CF                                                                           369  47% CF                                           Corrosion*                                                                             548  78% CF                                                                            --      --                                                  __________________________________________________________________________     *Exposed to 30 cycles each of: 5 hours at 158° F. 15 minutes 5%        sodium chloride solution; 19.25 hours 100° F./100% humidity.      

EXAMPLE III

This example demonstrates the need for an adhesion promotion system inthe composition. A set of partial compositions (i.e. containingpolyvinyl chloride resin containing but without a thermoplasticpolymeric resin) were made and then tested for short term and long termadhesion. The compositions are:

    ______________________________________                                        Parts by Weight                                                               ______________________________________                                        Homopolymer dispersion                                                                       20.0   20.0   20.0 20.0 20.0 20.0                              resin                                                                         Copolymer blending resin                                                                     8.4    8.4    8.4  8.4  8.4  8.4                               Calcium carbonate filler                                                                     39.8   39.8   39.8 39.8 39.8 39.8                              DIDP plasticizer                                                                             20.0   20.3   24.7 20.3 23.2 20.1                              t-butyl perbenzoate                                                                          0.08   0.08   0.08 0.08 0.08 0.08                              tribasic lead  1.1    1.1    1.1  1.1  1.1  1.1                               trimethylolpropane                                                                           4.7    --     4.7  4.7  4.7  4.7                               trimethacrylate                                                               methacrylate silane                                                                          0.3    0.3    --   0.3  0.3  0.3                               tetrahydrophtahlic                                                                           0.3    0.3    0.3  --   0.3  0.3                               anhydride                                                                     elastomeric modified epoxy                                                                   2.1    2.1    2.1  2.1  2.1  --                                resin                                                                         modified polyamide                                                                           3.2    3.2    3.2  3.2  --   3.2                               Adhesion Initial                                                                             10     8.5    1    9.5  3.5  10                                Adhesion 2 weeks at room                                                                     10     4.0    1    10   1    4                                 temperature                                                                   Adhesion 4 weeks at room                                                                     10     9.0    2    10   1    10                                temperature                                                                   ______________________________________                                    

Adhesion results were obtained as qualitative pulling of 1/2"×1/2" bendsof adhesive baked on a hot dipped galvanized panel for 6 minutes at 350°F. A rating of 10 was judged as best with 100% cohesive failure and arating of 0 was judged as worst with total adhesive failure coupled withlittle or no failing force. Separate adhesions were pulled for samplesmade fresh and then aged at room temperature for two and four weeksrespectively.

EXAMPLE IV

The composition in Example I can be modified to improve the paintabilityof the formulation. The composition of a paintable material is asfollows:

    ______________________________________                                                                    %                                                 ______________________________________                                        Polyvinyl chloride dispersion resin                                                                         19.00                                           Polyvinyl chloride blending resin                                                                           8.00                                            Diisodecyl phthalate plasticizer                                                                            8.00                                            Vinyl acetate ethylene copolymer thermoplastic resin                                                        13.00                                           3-methacryloxypropyl trimethoxy silane adhesion promoter                                                    0.30                                            Elastomeric modified liquid epoxy resin                                                                     2.00                                            Methacrylate ester adhesion promoter                                                                        4.50                                            Precipiated calcium carbonate filler (14)                                                                   16.80                                           Polyamino amide (15)          3.00                                            Calcium oxide filler          2.00                                            Cumene hydroperoxide          0.08                                            Tri-basic lead sulfate heat stabilizer                                                                      1.00                                            Hydroquinone monomethyl ether 0.02                                            Cis - 1, 2, 3, 6 - tetrahydrophthalic anhydride                                                             0.30                                            Polypropylene glycol dibenzoate plasticizer (16)                                                            10.00                                           Trioctyl trimellitate plasticizer                                                                           10.00                                           Polyadipic acid ester plasticizer (17)                                                                      2.00                                            ______________________________________                                         (14) Available from H. M. Royal as Hankuenka CC                               (15) Available from Sherex Chemical Company as Euretek 580                    (16) Available from Velsicol Chemical Corporation as Benzoflex 400            (17) Available from C. P. Hall as Plasthall P670                         

Modifications and variations of an obvious nature are possible withoutdeparting from the scope of the invention as defined in the appendedclaims.

What is claimed is:
 1. An adhesion promotion system for use withpolyvinyl chloride plastisol compositions and other adhesivecompositions in order to increase the adhesion of said compositions to ametal surface comprising:(a) 2.7 to 5.0% by weight of an unsaturatedorganosilane, (b) 54.0 to 40.0% by weight of an acrylic monomer, (c) 2.7to 10.0% by weight of an unsaturated acid or anhydride monomer, and (d)13.5 to 20.0% by weight of an epoxy resin or modified epoxy resin and27.0 to 25.0% by weight of a hardening agent for the epoxy resin ormodified epoxy resin.
 2. The system of claim 1 wherein said hardeningagent is selected from the group consisting of polyamides,diethylenetriamine, methane diamine, m-phenylene diamine,diaminodiphenyl sulfone, tris (dimethyl amino methyl) phenol,dicyandiamide, BF3-monoethyl amine and nadicmethyl anhydride.
 3. Thesystem of claim 1 wherein said unsaturated organosilane is selected fromthe group consisting of vinyl trichlorosilane, vinyl triethoxy silane,vinyl trimethoxy silane, vinyl-tris-B-methoxy-ethoxy silane, 3methacryloxypropyl trimethoxy silane, 3-methacryloxy propyl-tris-2(methoxy-ethoxy) silane and vinyl triacetoxy silane.
 4. The system ofclaim 3 wherein said acrylic monomer is selected from the groupconsisting of trimethylolpropane trimethacrylate, hexane dioldiacrylate, and butyl methacrylate.
 5. The system of claim 4 whereinsaid unsaturated acid or anhydride monomer is selected from the groupconsisting of maleic, acrylic, crotonic, methacrylic, oleic, linoleic,and tetrahydrophthalic acid or anhydride.
 6. The system of claim 5wherein said unsaturated organosilane is a methacrylate silane, saidacrylic monomer is trimethylolpropane trimethacrylate and saidunsaturated anhydride monomer is tetrahydrophthalic anhydride.
 7. Thesystem of claim 6 wherein said epoxy resin or modified epoxy resin is anelastomenic modified epoxy resin and said hardener is a modifiedpolyamide.
 8. An adhesion promotion system for use with polyvinylchloride plastisol compositions and other adhesive compositions in orderto increase the adhesion of said compositions to a metal surfacecomprising:a) 2.7 to 5.0% by weight of said adhesion promotion system ofan unsaturated organosilane selected from the group consisting of vinyltrichlorosilane, vinyl triethoxy silane, vinyl trimethoxy silane,vinyl-tris-B-methoxy-ethoxy silane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxy propyl-tris-2-(methoxy-ethoxy) silane, and vinyltriacetoxy silane; b) 54.0-40.0% of an acrylic monomer selected from thegroup consisting of trimethylolpropane trimethacrylate, hexane dioldiacrylate, and butyl methacrylate; and c) 2.7-10.0% of an unsaturatedacid or anhydride monomer.
 9. The system of claim 8 wherein saidunsaturated acid or anyhydride monomer is selected from the groupconsisting of maleic, acrylic, crotonic, methacrylic, oleic, linoleic,and tetrahydrophthalic acid or anhydride.
 10. The system of claim 9wherein said unsaturated organosilane is a methacrylate silane, saidacrylic monomer is trimethylolpropane trimethacrylate and saidunsaturated anhydride monomer is tetrahydrophthalic anhydride.
 11. Anadhesion promotion system for use with a polyvinyl chloride plastisolcompositions and other adhesive compositions in order to increase theadhesion of said compositions to a metal surface comprising:a) 2.7 to5.0 by weight of said adhesion promotion system of an unsaturatedorganosilane; b) 54.0 to 40.0% of an acrylic monomer; and c) 13.5 to20.0% of an epoxy resin or modified epoxy resin and 27.0% to 25.0% of ahardening agent for the epoxy resin or modified epoxy resin.
 12. Thesystem of claim 11 wherein said hardening agent is selected from thegroup consisting of polyamide, diethlenetriamine, methane diamine,m-phenylene diamine, diaminodiphenyl sulfone, tris (dimethyl aminomethyl) phenol, dicyandiamide, BF3-monoethly amine and nadicmethylanhydride.
 13. The system of claim 12 wherein said unsaturatedorganosilane is selcted from the group consisting of vinyltrichlorosilane, vinyl triethoxy silane, vinyl trimethoxy silane,vinyl-tris-B-methoxy-ethoxy silane, 3 methacryloxypropyl trimethoxysilane, 3-methacryloxy propyl-tris-2 (methoxy-ethoxy) silane and vinyltriacetoxy silane.
 14. The system of claim 13 wherein said acrylicmonomer is selected from the group consisting of trimethylolpropanetrimethacrylate, hexane diol diacrylate, and butyl methacrylate.